In reproduction systems, such as xerographic or other printers, it is often desirable to automatically compile each printed sheet of plural sheet documents in a collated and neatly superposed set, and then eject and stack such collated sets in an adjacent output tray or bin, with or without set stapling or other finishing, and/or with sets off-setting. Some examples are shown in Xerox Corp. U.S. Pat. Nos. 5,289,251 issued Feb. 22, 1994; 5,342,034 issued Aug. 30, 1994; and Xerox Corp. U.S. Statutory Invention Registration (SIR) No. H1781 published Feb. 2, 1999.
It may also be desirable in some situations for such printer output systems to reduce overall floor space or xe2x80x9cmachine footprint.xe2x80x9d Thus partial sharing of the set compiling and set stacking areas and functions may be optionally provided, such as also taught in Xerox Corp. U.S. Pat. No. 5,098,074 issued Mar. 24, 1992, or similar known systems in which the compiled sets are then fully ejected from the compiler tray by closing an open nip to engage driven sheet feeding rollers with mating idlers. Other compiling systems are cited in the above-cited patent publications.
In prior compiler/stacker systems such as those cited above, an exit feed nip providing the set ejection is typically held open during the compiling of all of the sheets of the set of sheets being compiled, especially if part of the sheets may stick out of the compiler during compiling, such in the type of system of the above-cited U.S. Pat. No. 5,098,074, or the like.
Of particular interest as an example of such exemplary prior art compiler/stacker systems is Xerox Corp. U.S. Pat. No. 5,473,420 issued Dec. 5, 1995, especially its following description in col. 6, lines 4-12. xe2x80x9cThe completed attached set can then be driven out of the tray 90 by set ejector driver rolls 109, 110 which come together to clamp the compiled set and move it onto the stacking tray 90.xe2x80x9d This typifies such prior systems in which the exit feed nip only closes after the set is fully compiled and stapled, to eject the entire compiled set fully out of the compiler onto an adjacent or downstream elevator or fixed stacking tray (or similarly into a selected xe2x80x9cmailboxxe2x80x9d bin, as in the above-cited U.S. Pat. No. 5,342,034 and SIR).
In contrast, the system of the specific disclosed embodiment further described below ejects the first sheet of each set being compiled partially out of the compiler system in an unusual way. When the first sheet of a set arrives at the compiler the compiler set eject drive roller nip system is closed, unlike the above-cited systems, and that first sheet""s lead area is fed partially out of the compiler downstream via the set eject drive rolls until the trail edge of that first sheet clears the compiler drive belt(s). At that point the rotation of the still-closed set eject drive rollers is reversed, by reversing their drive motor, to positively drive that first single sheet backwards (upstream) back into the compiler, under the compiler drive belt(s), to feed up against the compiler tray backstop. During or after that movement the set eject system nips are opened. The set eject nips can then remain open for the compiling of the rest of the set, and then close again to eject the compiled set and then to receive the first sheet of the next set to be compiled.
That is, the dual mode system of the disclosed embodiment uses the set eject system as an improved and more positive compiling drive system for the first sheet as well as providing for ejection of the completed set. It can also provides advantages in desensitizing sheet curl and/or making less critical the stacking tray angle, for reduced sheet jams or misstacking. This is particularly so where part of the stacking tray acts as supporting bridge for the compiling of the downstream end of the first sheet, especially for long sheets, as discussed above in connection with that cited art.
Further in that regard, finishing devices typically have a compiling technology that is sensitive to sheet curl. For mailbox systems, for example, the above-cited SIR No. H1781, since the mailbox bins or trays are typically not movable, the selected mailbox tray may even be miss-located at a distance vertically spaced from the exit point of the sheet from the compiler tray. Excessive curl generated by the printer may create what is usually called a completely curled over sheet lead edge or xe2x80x9croll over sheet,xe2x80x9d preventing proper collating or stacking of that or subsequent sheets. The typical consequence of such a xe2x80x9croll over sheetxe2x80x9d is that the next sheet of the set will jam, creating a printer or finisher shut down.
Problems with the compiling or stacking of curled sheets are greatly exacerbated by the typical space or gap between the downstream end of the compiler tray and the upstream end of the adjacent stacking tray or mailbox bin. That gap is unavoidable where the stacking tray is a typical vertically movable or elevator type stacking tray which must move down relative to the compiler output as it fills with multiple stacked sets from the compiler. Or, where a compiler unit must move vertically relative to plural mailbox bins, as in the above-cited and other references. A curled lead edge sheet can catch in this gap or stub on the entrance to the stacking tray, or stub on the upstream edge of a previously stacked set on the stacking tray.
A specific feature of the specific embodiment disclosed herein is to provide a method of compiling sets of plural printed sheets, and stacking plural said compiled sets, with an integral coupler/stacker system in which part of the plural sheets being compiled extend partially out of the compiler into the stacker, and in which a set eject system closes to eject compiled sets out of the compiler onto the stacker after they are fully compiled, the improvement comprising additionally closing said set eject system for the first sheet of a sheet set being compiled, feeding said sheet partially out onto said stacker with said set eject system, reverse feeding said first sheet of said set back into said compiler for compiling, opening said set ejection system for the subsequent sheets of said set, and closing said set ejection system again after said set is compiled for feeding said compiled set out of said compiler onto said stacker.
Further specific features disclosed in the embodiment herein, individually or in combination, include those wherein said set eject system comprises openable nip reversibly rotatably driven sheet feeding rollers in said compiler positioned adjacent to said stacker; and/or wherein said stacker is moveable relative to said compiler, with a gap therebetween, and said gap is covered by said first sheet of said set; and/or wherein said stacker is adapted to move relative to said compiler with a gap therebetween, said stacker is adjacent to said compiler and provides an extended sheet set compiling area for said compiler, said compiler is adapted to compile plural printed sheets into compiled sets of plural said sheets with part of said plural sheets being compiled extending partially out of said compiler into said stacker, said compiler further including a set eject system which closes to eject compiled sets out of the compiler onto the stacker after they are fully compiled, said set eject system comprising a selectably openable and closable dual mode sheet eject drive roller nips system adjacent to said stacker which automatically closes on the first sheet of a set being compiled to feed that first sheet partially out of said compiler towards said adjacent stacker to form a bridge over said gap between said stacker and said compiler, said selectably openable and closable dual mode sheet eject drive roller nips system being automatically reversible to reverse feed said first sheet set back into said compiler for positive compiling while retaining said bridge over said gap between said stacker and said compiler, said selectably openable and closable dual mode sheet eject drive roller nips system being automatically opened for the compiling of the subsequent sheets of that same set, and said selectably openable and closable dual mode sheet eject drive roller nips system being automatically closed again to eject an entire compiled set and receive said first sheet of the next set.
The disclosed system may be operated and controlled by appropriate operation of conventional control systems. It is well-known and preferable to program and execute imaging, printing, paper handling, and other control functions and logic with software instructions for conventional or general purpose microprocessors, as taught by numerous prior patents and commercial products. Such programming or software may of course vary depending on the particular functions, software type, and microprocessor or other computer system utilized, but will be available to, or readily programmable without undue experimentation from, functional descriptions, such as those provided herein, and/or prior knowledge of functions which are conventional, together with general knowledge in the software or computer arts. Alternatively, the disclosed control system or method may be implemented partially or fully in hardware, using standard logic circuits or single chip VLSI designs.
The term xe2x80x9creproduction apparatusxe2x80x9d or xe2x80x9cprinterxe2x80x9d as used herein broadly encompasses various printers, copiers or multifunction machines or systems, xerographic or otherwise, unless otherwise defined in a claim. The term xe2x80x9csheetxe2x80x9d herein refers to a usually flimsy physical sheet of paper, plastic, or other suitable physical substrate for images, whether precut or web fed. A xe2x80x9ccopy sheetxe2x80x9d may be abbreviated as a xe2x80x9ccopyxe2x80x9d or called a xe2x80x9chardcopy.xe2x80x9d A xe2x80x9cprint jobxe2x80x9d is normally a set of related sheets, usually one or more collated copy sets of printed sheets copied from a set of original document sheets or electronic document page images, from a particular user, or otherwise related. The terms nip and nips (plural) are used interchangeably herein because it will be well understood by those skilled in the art that there may be one, or more than one, mating drive rollers and idlers on the same shaft forming an effectively common nip. The term stacker as used herein broadly encompasses various elevator stacking trays or a stacking bin of a plural mailbox bins systems.
As to specific exemplary components of the subject apparatus or methods, or alternatives therefor, it will be appreciated that, as is normally the case, some such components are known per se in other apparatus or applications, which may be additionally or alternatively used herein, including those from art cited herein. For example, it will be appreciated by respective engineers and others that many of the particular component mountings, component actuation""s, or component drive systems illustrated herein are merely exemplary, and that the same novel motions and functions can be provided by many other known or readily available alternatives. All cited references, and their references, are incorporated by reference herein where appropriate for teachings of additional or alternative details, features, and/or technical background. What is well known to those skilled in the art need not be described herein.